1. Field of the Invention
The present invention relates to a sewing method and apparatus for overedge sewing the edge of a cloth to prevent raveling of the cloth edge cut in a desired shape for, say, slacks and skirts.
For such overedge sewing of a cloth edge, usually, an automatic serging machine is used. Generally, the automatic serging machine is equipped with a cloth guide plate, and a spacer disposed beneath the cloth guide plate, with a thickness corresponding to the cloth thickness. The cloth guide plate and spacer serve as a fitting guide of the cloth edge on a table before a presser foot of the serging machine. When the front end of the cloth fed from the operator's side on the table is detected by a sensor, the serging machine is started, and overedge sewing is done continuously and automatically until the rear end of the cloth is reached, while the cloth edge is guided under the presser foot by the cloth guide plate and the spacer.
2. Description of the Prior Art
Such automatic serging machines were hitherto disclosed in Japanese Utility Model Publication Sho. 56-46703, Japanese Patent Publication Sho. 60-43989, Sho. 57-1276, and Japanese Laid-open Patent Hei.1-268590, among others. The automatic serging machines disclosed in these publications are commonly designed to turn the cloth around the auxiliary presser until it abuts against a fitting guide for the edge guide before a needle drop point in order to guide and stitch a curved edge of the cloth.
In the conventional automatic serging machines, however, when a cut line of the curved edge is an out-curve, that is, curved outward of the machine, the curved edge can be securely sent into the needle drop point by a turning motion of the cloth, but when the cut line is an in-curve, the curved edge cannot be sent to the needle drop point unless the cloth is manually handled by the operator. That is, when serging the cloth having such an in-curved edge, the operator has to watch the cloth from start to end, which is one of the factors contributing to poor working efficiency.
Furthermore, in the conventional automatic serging machines, since the edge must be sewn on every side in order, the time loss is significant when it is necessary to watch the sewing of each cloth from start to end as mentioned above.